wilhelm lobenz



(No Model.)

W. LORENZ.-

METHOD 0F MAKING CARTRIDGE SHELLS.

Patented Aug. 3, 1886.

A TTOH//EYS N. versus Pmmumognyw. wnhingm n.6.

IOv

NrTED STATES PATENT EEreEo lVIETHOD OF MAKING CARTRIDGE-SHELLS.

SPECIFICATION forming part of Letters Patent No. 346,759, dated August3, 1886.

Application filed January 17, 1885. Serial No. 153.136.

(No model.) Patented in Germany May G, 1884, No. 30,275; in France June20, 1884, No. 162,862; in England July 28, 1884, No. 10,688; in BelgiumAugust 14, 1884, No. 66,030; in Sweden September 29, 1884; in Italy,September 30,1884,No. 17,250 and No. 189; in AusiriaHungary October 31,1884, No. 31,515 and No. 50,080; in Spain November 5, 1884, No. Gli, andin Norway December 5, 1884.

To all whom it may concern:

Be it known that I, WILHELM LORENZ, of

.Oarlsruhe, in the Grand Duchy of Baden and G. Vol. XVIII, No. 17,250,and R. A. Vol.

XXXIV, No. 189; Austria-Hungary, dated October 31,1884,Tom. 84, fol.2,120, No. 31,515, and Tom. XVIII, fol. 2,108, No. 50,680;

Spain, dated November 5, 1884, fol. 428, No.-

63, and Norway, December 5, 1884,) of which the following is aspecification.

rIhe employment of metallic eartridgeshells for field pieces and guns oflarger caliber offers a number of essential advantages in theconstruction as well as in the manipulation of the same, as compared tothe packing heretofore in use, which consisted of a bag of textilefabric. Metallic shells, for instance, furnish a tight and reliablepacking between the barrel and breech-block. They prevent injury to theinner surface of the barrel, and dispense with separate packings-such assabots, disks, &e. With cartridges having metallic shells it is possibleto use percussion-primers,whereby the friction priming with itstouch-hole screw and packing, Ste., is obviated. 'Ihe metallic shellsalso prevent the settling of the products of combustion in the barrel,while by the employment of suitable wads for closing the metallic shellsat their mouths, the cartridge-chamber as well as the inner rifledsurface of the barrels are cleaned, and the long Wiper for cleaning thegun-barrels done away.

with. V

The most essential conditions which are necessary for the properintroduction of metallic cartridge-shells for heavy guns are, first,that the shells, notwithstanding their size, 'have to be made of verythin sheet metal and aslight as possible, so that the weight exerted onthe trunnions is but little increased. A second condition is that theshells, notwithstanding their reduced thickness, have to be tough and ofgreat strength andk resistibility, so that they can be used severaltimes for avoiding too great expense, especially in practice firingA Themanufacture of suchthin shells possessing the required degree ofresistibility could not be properly accomplished by the methodheretofore in use for making cartridge-shells of smaller sizes, as thedegree of lightness and strength required for resisting the force of theexplosion could not be obtained thereby. It

. is therefore necessary to provide anl entirely new method whichdiffers fromthe one heretofore in use for producing cartridgeshells forlargersizes of projectiles for artillery purposes.

rIlhe method heretofore in use for making shells for smaller cartridgesconsists, first, in the use of sheet-metal disks or blanks of athickness which is in a certain fixed proportion to the thickness of thebottom of the shell to be formed, but which thickness turns out in mostcases to be greater in the finished shells; secendl y, by pressing anddrawing the blank from a larger diameter to a smaller diameter, andshaping the bottom from the exterior circumference and side wall towardthe center; thirdly, by forming the side wall of the shell only fromthat part of the blank that forms the side wall of the cup obtained bythe first pressing. It is a characteristic feature of this method ofmaking cartridge-shells that in the first stages of their production,not only the thickness of the metal in the bottom is retained, but thatthe same is increased by the inward crowding of the stock in obtainingthe required dimension of the rim, the proper thickness of the bottom,and the proper shape of the primingcup. It follows, therefore, that `forshells with thick bottoms thick blanks, and for shells with thinbottomsthin blanks, have to be used, and that in the manufacture ofcartridge-shells with thin bottoms from thin blanks, owing to the easyworking up of the material, but little power is required. It follows,vfurther, that the shell is drawn out over and over again at the point ofconnection of the bottom with the side wall, while the main part of thebottom remains intact, by which the strength of the material is mostinjuriously affected at the point where it should be strongest, so thatfrequently transverse breaks are formed, which render the shellunfit'for use.l It is not possible to avoid this defect by increasingthe thickness of the shell at the point referred to by giving it alarger crosssection, and decreasing gradually its thickness from thebottom to the side wall, because, even if the breaks do not penetrate atfirst through the entire thickness of the side wall, they gradlr allyincrease in depth in firing until they pass through the wall of theshell. It is therefore clear that by using the method heretoforereferred to for making shells for cartridges for guns of heavy size-suchas field-pieces or other heavy guns--the thickness of the sheet metal lhas to be so selected that the priming-cup and rim can be formed fromthe same, that further the bottom retains the thickness of theblankdisk, and that the bent-up side wall of the cup formed from theblank has to form the side wall of the shell. These conditions requirethat the bottom of the shell would have to be very thick', and that,consequently, the weight of the shell would be considerably increased.This additional weight forms a serious objection, as it would eventuallypreclude the use of metallic shells for heavy projectiles, owing to theincreased weight and the increased strain on the carriage.

My improved method of making cartridgeshells for projectiles of largesizes avoids the above-mentioned objections, and the invention consistsof a method of making metallic shells of large size in which all thestock that is not required in the bottom for the formation of thepriming-cup and the rim is first `forced by pressure from the bottomtoward its circumference, and then drawn from the circumference into theside wall of the shell. It is therefore possible to make shells withthin bottoms from thick blanks or disks by gradually crowding the metalin a series of concentric rings or radially from the center toward theperiphery, whereby the strength of the shells at the point of connectionof the bottom with the cylindrical side wall is increased. Y

In the accompanying drawings, Figures 1 to 8 show the different stagesthrough which the 5 blank has to pass in forming a shell, together withthe dies for bending, drawing, pressing,

and forming the rim of the blank. Fig. 9 is a vertical longitudinalsection of a finished shell.

Similar letters of reference indicate correspending parts.

In carrying out my invention a thick blank, a, of disk shape (shown indotted lines in Fig. l) is first bent into cup shape in the usualmanner. The blank-cu p bis then exposed to pressure, so as to form theprimingcup c from the stock at the central part of the bottom, while thestock immediately around the primingcup is forced in outward direction,as shown in Fig. 2. In the following stages of the pressing operation(shown in Figs. 3 and 4) the stock is crowded from the center toward thecircumference, whereby the diameter of the bottom is enlarged, thethickness of the same diminished, and a thick annular portion, d, formedat` the circumference. From the annular portion d the stock is conveyedby drawing, as shown in Fig. 5, into the cylindrical side wall, g, ofthe shell, which drawing is continued, so that the shell is graduallylengthened, as shown in Figs. 6 and 7.

It appears clearly from the Figs. 1 to 7, that the thickness of thebottom decreases successively, and that the stock is gradually crowdedfrom the center toward the periphery of the bottom, and from the same ina continuous fiber into the side wall of the shell, while suffieientquantity of stock is retained for forming the rim r of the shell, asshown in Fig. 9.

The filial formation of the rim 1 takes place in an analogous manner bycrowding the stock ,from the center toward the circumference. This isaccomplished by pressing the bottom first into proper shape from theinside by means of a straight and smooth die, as shown in Fig. 8, sothat the next following pressure on the outside by the die which formsthe rim (also shown inA Fig. 8) cannot force the stock back toward thecenter. As the bottom is compressed by the first pressure, the stock inthe annular portion d, being of softer metal, can only fiow in outwarddirection. Without this preparatory pressing the stock would bedistributed over the bottom, and thereby an increase in the thickness ofthe same obtained,

which is the very object to be prevented.

It is obvious that by crowding the stock from the center of the bottomtoward the circumference by means of one or more successive pressings,the grain-like structure of the metal is gradually changed to a fibrousstructure that extends radially from the center to the circumference,and which extends by the successive pressing and drawing into the rimand from the same into the side Wall of the shell, as indicated in Figs.1 to 8, in which the continuity of thebre is clearly indicated. It isalso obvious that by thus imparting a fibrous structure to themetal nopart of the shell is injuriously affected, so that, consequently, noweak spots are formed near the rims or cross-breaks, owing to thelongitudinal direction of the fibers.

My improved method of making larger sizes of shells has the advantagethat blanks of any desired thickness may be used, as said thickness isreduced in the course of manufacture to the required thickness of thebottom, and the superfluous stock crowded into the side wall of theshell, in which it is drawn out to the required thickness, and finallycut off to the required length. All that is necessary in selecting thethickness of the blanks is to have proper regard for the thickness ofmetal required for the priming-cup, and for the desired weight of thefinished shell. ,It follows, therefore, that the dimensions of theblanks can be determined accurately and with a view to the mosteconomical distribution of the stock. rlhe improved method requires,how- 4 ever, in contradistincticn to the method heretofore in use formaking shells fromthin sheet metal, powerful pressures, so as to producethe thin bottoms from the blanks of greater thickness.

In the same manner as cartridgeshells other hollow sheet-metal bodiescan be made according to the method described, either with centraldepressions in the nature of the primingcups, or with ring-shapeddepressions, or with solid projecting rims, or with hollow rims. Mymethod is therefore adapted to make all kinds of seamless cylindricalbodies from any suitable metal, such as cans, boxes, vessels, and otherarticles.

Having thus described my invention,I claim as new and desire'to secureby Letters Patent- 1. The method herein described of making large sizedcartridge-shells and other hollow sheet-metal bodies, which consists incrowding the stock by successive pressings from the center of the bottomof the blank toward the circumference, and then drawing the samegradually into the side Wall of the shell or other body, substantiallyas set forth.

2. The method herein described of making large-sized cartridge-shellsand other hollow sheet-metal bodies, which consists in reducing thethickness of the disk-shaped blank by crowding the stock from the centerof the blank toward the circumference by successive pressings, thendrawing gradually the stock from the circumference into the side wall ofthe shell or other body, shaping the bottom and increasing the strengthby inside pressure, and finally forming the rim at the periphery of thebody, substantially as set forth.

In testimony that I claim the foregoing as my invention I have signed myname in pres ence of two subscribing witnesses.

VILHELM LORENZ.

